Spica
The title of this article is ambiguous. For other meanings, see Spica (disambiguation).
Database links to Spica / α Virginis
Spica (Latin for ear of corn), also called α Virginis, Azimech, or Alaraph, is the brightest star in the constellation Virgo and the fifteenth brightest star in the night sky.
In the constellation of Virgo, Spica represents the ear of grain in the hand of Virgo. In Mesopotamia, Spica was known as dšala šubultu (God/Goddess Schala, the Ear of Corn), later also Divine Maiden of the Ear of Corn. The Romans believed to see in Spica the goddess Ceres. Roman names are Spicum, Spigha, Stachys (from Gr. stakhum corn ear) and Aristae Puella (corn maiden).
The IAU adopted the proper name Spica as a standardized proper name on June 30, 2016.
Spica is a spectroscopic binary (A/B) and an ellipsoid variable star. Spica A is a pulsation variable star of the Beta Cephei type. The brightness of Spica changes with a period of 4.0142 days between +0.92 mag and +0.98 mag. This small variation in brightness is hardly detectable visually.
Both components of Spica are of spectral type B (B1 to B4), with the brighter star near the end of its stable period as a main sequence star. The two stars are among the hottest and thus bluest of the bright stars in the night sky. Due to their high temperature, much of their light is emitted in the invisible ultraviolet range. The irradiance of both stars together is greater than the irradiance of the brightest fixed star Sirius, yet Sirius appears brighter to the eye than Spica.
The brighter star has a temperature of 25,300 K and a luminosity 20,512 times that of the Sun. The radius is 7.8 times the radius of the Sun and extends to nearly 30% of the distance between the two stars. The mass of the brighter star is eleven times that of the Sun. This is enough to make the star end up as a supernova.
The not so well known less bright companion star has a surface temperature of 20,900 K, 2,254 times solar luminosity, four times solar radius and slightly less than seven times solar mass.
As a star close to the ecliptic, Spica can be occulted by the Moon and (very rarely) by planets. For the last time Spica was occulted by a planet on November 10, 1783 by Venus, the next occultation will be on September 2, 2197 again by Venus.
Spica is depicted in the flag of Brazil, where he represents the state ofPará.
Spica is the brightest star in the constellation Virgo (lower left).
See also
- List of the brightest stars
- Spring Sky
